Preparation method of Ru embedded in TiO2 lattice rich heterojunction interface hydrogen hydroxide evolution electrocatalyst

Abstract

The present invention belongs to the technical field of hydroxide exchange membrane fuel cells and water electrolysis, and in particular to a preparation method of a Ru-embedded TiO2 lattice-rich heterojunction interface hydrogen hydroxide precipitation electrocatalyst, comprising: dissolving 2-aminoterephthalic acid in ethanol and N,N-dimethylformamide, adding ruthenium salt, ultrasonicating under room temperature, adding isopropyl titanate after complete dissolution, and obtaining Ru-doped NH2-MIL-125(Ti) metal organic framework through a hydrothermal strategy. Further adding ruthenium salt to make Ti in the Ru-doped NH2-MIL-125(Ti) metal organic framework 4+ With Ru 3+ Metal cation exchange, by controlling the temperature and time of carbonization, Ru single atoms and reduced Ru metal clusters can be better embedded in the TiO2 lattice to form a rich heterojunction interface. In addition, there are a large number of Ru-Ti bonds at the heterojunction interface, which increases the number of active sites, ensures the effective transfer of electrons from Ti to Ru, and gives the Ru active sites a low metallic valence state.

Description

Technical Field

[0001] The invention relates to the technical field of hydroxide exchange membrane fuel cells and water electrolysis, and in particular to a method for preparing a Ru-embedded TiO2 lattice-rich heterojunction interface hydrogen hydroxide precipitation electrocatalyst. Background Art

[0002] Hydrogen energy is considered an ideal form of clean energy due to its high energy and zero greenhouse gas emissions. Electrochemical water splitting electrolyzers and fuel cells are key technologies for realizing the hydrogen economy. In current applications, the costs of proton exchange membrane fuel cells and electrolyzers have remained high for a long time, and hydroxide exchange membrane fuel cells and electrolyzers are considered to be the next-generation technologies with the greatest potential for commercial application. Hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) are the key half-reactions of fuel cells and water electrolyzers, but the reaction rates of alkaline HOR and HER are 2 to 3 orders of magnitude lower than those in acidic media, which seriously restricts the development of alkaline fuel cells and electrolyzers. Therefore, the design and development of low-cost, efficient and stable hydrogen electrode electrocatalysts is the key to promoting the development of the hydrogen economy.

[0003] Among the Pt group elements, Ru, which is only 4-50% of Pt in price, has attracted much attention due to its rich redox electrochemical properties. However, due to Ru's strong hydrogen bonding energy, the H ad It is difficult to desorb, and the HOR / HER activity of most Ru-based electrocatalysts is still lower than that of commercial Pt / C. In addition, Ru-based nanocrystals have strong oxygen-containing species bonding ability, which easily over-adsorbs oxygen-containing species under high potential conditions (>0.1 V vs. RHE, three-electrode system), resulting in a decrease in the number of Ru active sites for H2 adsorption and dissociation, and the alkaline HOR activity gradually decreases with increasing potential. Bare Ru nanocrystals are easily poisoned by CO in H2 obtained from methane reforming or coal gasification. Therefore, it is of great and practical significance to introduce other species to modulate the electron distribution on the Ru metal surface and construct Ru-based alkaline HOR / HER electrocatalysts with high activity, CO resistance, and stability at high potential. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method for preparing a Ru-embedded TiO2 lattice-rich heterojunction interface hydrogen hydroxide evolution electrocatalyst to solve the problems raised in the background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for preparing a Ru-embedded TiO2 lattice-rich heterojunction interface hydrogen hydroxide evolution electrocatalyst, characterized in that it comprises the following steps:

[0007] Step 1: Prepare the precursor. The specific steps are as follows:

[0008] (1) Dissolve 2-aminoterephthalic acid in ethanol and N,N-dimethylformamide, and add ruthenium salt;

[0009] (2) Ultrasonicate under room temperature, and add isopropyl titanate after it is completely dissolved;

[0010] (3) Ultrasonicate again. After complete dissolution, transfer the solution into a polytetrafluoroethylene-lined reactor and react in an oven at 150 °C for 24 hours.

[0011] (4) washing by centrifugation and drying to obtain Ru-doped NH2-MIL-125(Ti) metal organic framework;

[0012] (5) Prepare ruthenium salt and add it to the Ru-doped NH2-MIL-125(Ti) metal organic framework suspension dispersed in deionized water. Stir magnetically at room temperature for 24 hours to allow the Ru metal cation added later to successfully bind to the Ti in the metal organic framework. 4+ Ion exchange;

[0013] (6) After completion, centrifuge, wash, and dry to obtain the precursor;

[0014] Step 2: Preparation of Ru embedded in TiO2 lattice rich heterojunction interface hydrogen hydroxide evolution electrocatalyst

[0015] The precursor obtained in step 1 is placed in a tube furnace, and carbonized for 2 to 4 hours under a protective atmosphere and a temperature of 400 to 800 °C, thereby finally obtaining a hydrogen hydroxide evolution electrocatalyst with Ru embedded in the TiO2 lattice and rich in heterojunction interfaces.

[0016] Preferably, in step 1 (1) and (5), the ruthenium salt is one or more of ruthenium chloride, nitrate compound and acetylacetone compound.

[0017] Preferably, in step 1 (1), the concentration of 2-aminoterephthalic acid in the ethanol / N,N-dimethylformamide mixed solution is 1-10 mg mL -1 .

[0018] Preferably, in step 1 (1), the mass of the ruthenium salt is 0-100 mg.

[0019] Preferably, in step 1 (2), the concentration of isopropyl titanate in the ethanol / N,N-dimethylformamide mixed solution is 1-10 µL mL -1 .

[0020] Preferably, in step 1 (5), the concentration of the ruthenium salt is 1-10 mg mL-1 .

[0021] Preferably, in step 1 (5), the concentration of the Ru-doped NH2-MIL-125(Ti) metal organic framework dispersed in deionized water is 1-10 mg mL -1 .

[0022] Preferably, in step 1 (2) and (3), the ultrasonication time is 5 to 60 min.

[0023] Preferably, in step 2, the protective atmosphere is one or a mixture of two or more of helium, argon, nitrogen and hydrogen.

[0024] Preferably, in step 2, Ru is embedded into the TiO2 lattice in the form of single atoms and clusters.

[0025] The second aspect of the present invention provides a Ru-embedded TiO2 lattice-rich heterojunction interface electrocatalyst for hydrogen hydroxide evolution.

[0026] The third aspect of the present invention provides the application of Ru embedded in TiO2 lattice rich heterojunction interface hydrogen hydroxide evolution electrocatalyst in hydroxide exchange membrane fuel cell and water electrolysis device.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention firstly uses hydrothermal method to prepare Ru-doped Ti-MOF, and then uses ion exchange to make Ru metal cations react with Ti in Ru-doped Ti-MOF. 4+ Ion exchange and finally carbonization. The obtained electrocatalyst is rich in interfaces and Ru-Ti bonds, which increases the electron transmission efficiency, greatly improves the activity of Ru in HOR / HER electrocatalytic reactions, the antioxidant capacity at high potentials, and the poisoning resistance under 100 ppm CO conditions, and also provides a new idea for reducing the cost of electrocatalysts for fuel cells and electrolyzers and realizing the hydrogen economy.

[0029] 2. The preparation method of the present invention is novel. The Ru-doped NH2-MIL-125(Ti) metal organic framework is prepared by using a hydrothermal strategy. Ruthenium salt is further added to make the Ti in the Ru-doped NH2-MIL-125(Ti) metal organic framework 4+ With Ru 3+ Metal cation exchange, by controlling the temperature and time of carbonization, Ru single atoms and reduced Ru metal clusters can be better embedded in the TiO2 lattice to form a rich heterojunction interface. In addition, there are a large number of Ru-Ti bonds at the heterojunction interface, which increases the number of active sites, ensures the effective transmission of electrons from Ti to Ru, and gives the Ru active sites a low metallic valence state.

[0030] 3. The Ru prepared in the present invention is co-embedded in the TiO2 lattice in the form of single atoms and clusters, is rich in heterojunction interfaces, has excellent electrocatalytic activity for hydrogen hydroxide evolution, outstanding high potential stability and resistance to CO poisoning, and demonstrates its great potential for application in hydroxyl exchange membrane fuel cells and water electrolysis devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a scanning electron microscope image (SEM) of the precursor in Example 1 of the present invention;

[0032] Figure 2 This is a SEM image of the hydrogen hydroxide evolution electrocatalyst having Ru embedded in the TiO2 lattice and rich in heterojunction interface in Example 1 of the present invention;

[0033] Figure 3 This is a transmission electron microscopy (TEM) image of the hydrogen hydroxide evolution electrocatalyst having Ru embedded in the TiO2 lattice rich heterojunction interface in Example 1 of the present invention;

[0034] Figure 4 Spherical aberration corrected scanning transmission electron microscopy (AC-STEM) image of hydrogen hydroxide evolution electrocatalyst with Ru embedded in TiO2 lattice rich heterojunction interface in Example 1 of the present invention;

[0035] Figure 5 The alkaline hydrogen oxidation polarization curves of the hydrogen hydroxide evolution electrocatalyst with Ru embedded in the TiO2 lattice rich heterojunction interface and the commercial platinum / carbon electrocatalyst in Example 1 of the present invention;

[0036] Figure 6 The chronoamperometric curves of the hydrogen hydroxide evolution electrocatalyst with Ru embedded in the TiO2 lattice rich heterojunction interface and the commercial platinum / carbon electrocatalyst under 1.2 V vs. RHE and pure H2 conditions in Example 1 of the present invention;

[0037] Figure 7 The chronoamperometric curves of the Ru-embedded TiO2 lattice-rich heterojunction interface hydrogen hydroxide evolution electrocatalyst and the commercial platinum / carbon electrocatalyst under 0.1 V vs. RHE, CO (100 ppm) / H2 conditions in Example 1 of the present invention;

[0038] Figure 8 The alkaline hydrogen evolution polarization curves of the hydrogen evolution electrocatalyst with Ru embedded in the TiO2 lattice rich heterojunction interface in Example 1 of the present invention and the commercial platinum / carbon electrocatalyst. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] The platinum / carbon (20 wt %, Johnson Matthey) in the following examples was purchased from commercial sources. Example

[0041] (1) Preparation of precursor

[0042] 2-Aminoterephthalic acid (0.28 g) was dissolved in ethanol (20 mL) and N,N-dimethylformamide (20 mL), and 10 mg of ruthenium trichloride was added. Ultrasonication was performed at room temperature for 30 min. After complete dissolution, isopropyl titanate (0.3 mL) was added and ultrasonication was performed again for 5 min. After complete dissolution, the solution was transferred to a polytetrafluoroethylene-lined reactor and reacted in an oven at 150 °C for 24 hours. After centrifugation, washing, and drying, Ru-doped NH2-MIL-125(Ti) metal organic framework was obtained. 2 mg mL -1 The ruthenium trichloride was added to a suspension of Ru-doped NH2-MIL-125(Ti) metal organic framework (72 mg) dispersed in deionized water (20 mL) and magnetically stirred at room temperature for 24 h, so that the Ru metal cation added later successfully combined with the Ti in the metal organic framework. 4+ After ion exchange, centrifuge, wash and dry to obtain the precursor.

[0043] (2) Preparation of Ru embedded in TiO2 lattice rich heterojunction interface electrocatalyst for hydrogen evolution

[0044] The obtained precursor was placed in a tube furnace and carbonized for 3 h in a 5% H2 / Ar atmosphere at 500 °C to finally obtain a hydrogen hydroxide evolution electrocatalyst with Ru embedded in the TiO2 lattice and rich in heterojunction interfaces.

[0045] like Figure 1 ,SEM results show that the precursor obtained in step (1) is a flower-like nanosheet structure;

[0046] like Figure 2 , SEM results show that the Ru embedded in the TiO2 lattice obtained in step (2) is rich in heterojunction interface hydrogen hydroxide evolution electrocatalyst with irregular flake structure;

[0047] like Figure 3,TEM results show that the Ru embedded in the TiO2 lattice obtained in step (2) is rich in heterojunction interfaces, and the surface of the hydrogen hydroxide evolution electrocatalyst is rich in heterojunction interfaces;

[0048] like Figure 4 , AC-STEM results show that the Ru embedded in the TiO2 lattice obtained in step (2) is rich in the heterojunction interface of the hydrogen hydroxide evolution electrocatalyst interface, and the interface is rich in Ru-Ti bonds, and Ru is co-embedded in the TiO2 lattice in the form of single atoms and clusters;

[0049] like Figure 5 The prepared Ru-embedded TiO2 lattice-rich heterojunction interface hydrogen hydroxide evolution electrocatalyst has better alkaline HOR activity than commercial Pt / C;

[0050] like Figure 6 The high potential anti-oxidative stability of the prepared Ru-embedded TiO2 lattice-rich heterojunction interface hydrogen hydroxide evolution electrocatalyst is superior to that of commercial Pt / C;

[0051] like Figure 7 The prepared Ru-embedded TiO2 lattice-rich heterojunction interface hydrogen hydroxide evolution electrocatalyst has better CO tolerance than commercial Pt / C;

[0052] like Figure 8 The prepared Ru-embedded TiO2 lattice-rich heterojunction interface hydrogen hydroxide evolution electrocatalyst has better alkaline HER activity than commercial Pt / C. Example

[0053] (1) Preparation of precursor

[0054] 2-Aminoterephthalic acid (0.14 g) was dissolved in ethanol (20 mL) and N,N-dimethylformamide (20 mL), and 20 mg of ruthenium trichloride was added. Ultrasonication was performed at room temperature for 30 min. After complete dissolution, isopropyl titanate (0.2 mL) was added and ultrasonication was performed again for 10 min. After complete dissolution, the solution was transferred to a polytetrafluoroethylene-lined reactor and reacted in an oven at 150 °C for 24 hours. After centrifugation and washing, Ru-doped NH2-MIL-125(Ti) metal organic framework was obtained after drying. 4 mg mL -1 The ruthenium trichloride was added to a suspension of Ru-doped NH2-MIL-125(Ti) metal organic framework (72 mg) dispersed in deionized water (20 mL) and magnetically stirred at room temperature for 24 h, so that the Ru metal cation added later successfully combined with the Ti in the metal organic framework. 4+ After ion exchange, centrifuge, wash and dry to obtain the precursor.

[0055] (2) Preparation of Ru embedded in TiO2 lattice rich heterojunction interface electrocatalyst for hydrogen evolution

[0056] The obtained precursor was placed in a tube furnace and carbonized for 3 hours in a 10% H2 / Ar atmosphere at 500°C to finally obtain a hydrogen hydroxide evolution electrocatalyst with Ru embedded in the TiO2 lattice and rich in heterojunction interfaces. Example

[0057] (1) Preparation of precursor

[0058] 2-Aminoterephthalic acid (0.28 g) was dissolved in ethanol (20 mL) and N,N-dimethylformamide (20 mL), and 10 mg of ruthenium trichloride was added. Ultrasonication was performed at room temperature for 40 min. After complete dissolution, isopropyl titanate (0.3 mL) was added and ultrasonication was performed again for 5 min. After complete dissolution, the solution was transferred to a polytetrafluoroethylene-lined reactor and reacted in an oven at 150 °C for 24 hours. After centrifugation, washing, and drying, Ru-doped NH2-MIL-125(Ti) metal organic framework was obtained. 2 mg mL -1 The ruthenium trichloride was added to a suspension of Ru-doped NH2-MIL-125(Ti) metal organic framework (72 mg) dispersed in deionized water (20 mL) and magnetically stirred at room temperature for 24 h, so that the Ru metal cation added later successfully combined with the Ti in the metal organic framework. 4+ After ion exchange, centrifuge, wash and dry to obtain the precursor.

[0059] (2) Preparation of Ru embedded in TiO2 lattice rich heterojunction interface electrocatalyst for hydrogen evolution

[0060] The obtained precursor was placed in a tube furnace and carbonized for 3 h under Ar atmosphere and 600 °C, and finally a hydrogen hydroxide evolution electrocatalyst with Ru embedded in the TiO2 lattice and rich in heterojunction interface was obtained. Example

[0061] (1) Preparation of precursor

[0062] 2-Aminoterephthalic acid (0.28 g) was dissolved in ethanol (20 mL) and N,N-dimethylformamide (20 mL), and 10 mg of ruthenium nitrate was added. Ultrasonication was performed at room temperature for 30 min. After complete dissolution, isopropyl titanate (0.3 mL) was added and ultrasonication was performed again for 5 min. After complete dissolution, the solution was transferred to a polytetrafluoroethylene-lined reactor and reacted in an oven at 150 °C for 24 hours. After centrifugation and washing, Ru-doped NH2-MIL-125(Ti) metal organic framework was obtained after drying. 2 mgmL -1Ruthenium nitrate was added to a suspension of Ru-doped NH2-MIL-125(Ti) metal organic framework (100 mg) dispersed in deionized water (20 mL) and magnetically stirred at room temperature for 24 h, so that the Ru metal cation added later successfully combined with the Ti in the metal organic framework. 4+ After ion exchange, centrifuge, wash and dry to obtain the precursor.

[0063] (2) Preparation of Ru embedded in TiO2 lattice rich heterojunction interface electrocatalyst for hydrogen evolution

[0064] The obtained precursor was placed in a tube furnace and carbonized for 4 h in a 5% H2 / N2 atmosphere at 500 °C to finally obtain a hydrogen hydroxide evolution electrocatalyst with Ru embedded in the TiO2 lattice and rich in heterojunction interfaces. Example

[0065] (1) Preparation of precursor

[0066] 2-Aminoterephthalic acid (0.56 g) was dissolved in ethanol (20 mL) and N,N-dimethylformamide (20 mL), and 20 mg of ruthenium acetylacetonate was added. Ultrasonication was performed at room temperature for 30 min. After complete dissolution, isopropyl titanate (0.3 mL) was added and ultrasonication was performed again for 5 min. After complete dissolution, the solution was transferred to a polytetrafluoroethylene-lined reactor and reacted in an oven at 150 °C for 24 hours. After centrifugation, washing, and drying, Ru-doped NH2-MIL-125(Ti) metal organic framework was obtained. 4 mg mL -1 The Ru(II) acetylacetonate was added to a suspension of Ru-doped NH2-MIL-125(Ti) metal organic framework (72 mg) dispersed in deionized water (20 mL) and magnetically stirred at room temperature for 24 h, so that the Ru metal cation added later successfully bound to the Ti in the metal organic framework. 4+ After ion exchange, centrifuge, wash and dry to obtain the precursor.

[0067] (2) Preparation of Ru embedded in TiO2 lattice rich heterojunction interface electrocatalyst for hydrogen evolution

[0068] The obtained precursor was placed in a tube furnace and carbonized for 2 h under Ar atmosphere and 550 °C to finally obtain a hydrogen hydroxide evolution electrocatalyst with Ru embedded in the TiO2 lattice and rich in heterojunction interface. Example

[0069] (1) Preparation of precursor

[0070] 2-Aminoterephthalic acid (0.28 g) was dissolved in ethanol (20 mL) and N,N-dimethylformamide (20 mL). Ultrasonication was performed at room temperature for 20 min. After complete dissolution, isopropyl titanate (0.3 mL) was added and ultrasonication was performed again for 20 min. After complete dissolution, the solution was transferred to a polytetrafluoroethylene-lined reactor and reacted in an oven at 150 °C for 24 hours. After centrifugation and washing, NH2-MIL-125(Ti) metal organic framework was obtained after drying. 2 mg mL -1 The ruthenium trichloride was added to a suspension of NH2-MIL-125 (Ti) metal organic framework (72 mg) dispersed in deionized water (20 mL) and magnetically stirred at room temperature for 24 hours, so that the Ru metal cation added later successfully combined with the Ti in the metal organic framework. 4+ After ion exchange, centrifuge, wash and dry to obtain the precursor.

[0071] (2) Preparation of Ru embedded in TiO2 lattice rich heterojunction interface electrocatalyst for hydrogen evolution

[0072] The obtained precursor was placed in a tube furnace and carbonized for 3 hours in a 10% H2 / He atmosphere at 700°C to finally obtain a hydrogen hydroxide evolution electrocatalyst with Ru embedded in the TiO2 lattice and rich in heterojunction interfaces.

[0073] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A method for preparing a Ru-embedded TiO2 lattice-rich hydrogen hydroxide evolution electrocatalyst with a heterojunction interface, characterized in that: The steps include: Step 1: Prepare the precursor. The specific steps are as follows: (1) Dissolve 2-aminoterephthalic acid in ethanol and N,N-dimethylformamide, and add ruthenium salt; the concentration of 2-aminoterephthalic acid in the ethanol / N,N-dimethylformamide mixed solution is 1-10 mg mL -1 ; The mass of the ruthenium salt is 0~100 mg; (2) Ultrasonication at room temperature, after complete dissolution, add isopropyl titanate; the concentration of isopropyl titanate in the ethanol / N,N-dimethylformamide mixed solution is 1~10 µL mL -1 ; (3) Ultrasonicate again. After complete dissolution, transfer the solution into a polytetrafluoroethylene-lined reactor and react in an oven at 150 °C for 24 hours. (4) washing by centrifugation and drying to obtain Ru-doped NH2-MIL-125(Ti) metal organic framework; (5) Prepare ruthenium salt and add it to the Ru-doped NH2-MIL-125(Ti) metal organic framework suspension dispersed in deionized water. Stir magnetically at room temperature for 24 hours to allow the Ru metal cation added later to successfully bind to the Ti in the metal organic framework. 4+ Ion exchange; the concentration of the ruthenium salt is 1~10 mg mL -1 The concentration of the Ru-doped NH2-MIL-125 (Ti) metal organic framework dispersed in deionized water is 1~10 mg mL -1 ; (6) After completion, centrifuge, wash, and dry to obtain the precursor; Step 2: Preparation of Ru embedded in TiO2 lattice rich heterojunction interface hydrogen hydroxide evolution electrocatalyst The precursor obtained in step 1 is placed in a tubular furnace, and carbonized for 2 to 4 hours under a protective atmosphere and a temperature of 400 to 800°C, to finally obtain a hydrogen hydroxide evolution electrocatalyst with Ru embedded in the TiO2 lattice and rich in heterojunction interface; the protective atmosphere is one or a mixed gas of more than two of helium, argon, nitrogen, and hydrogen; and Ru is embedded in the TiO2 lattice in the form of single atoms and clusters.

2. The method for preparing a Ru-embedded TiO2 lattice-rich heterojunction interface hydrogen hydroxide evolution electrocatalyst according to claim 1, characterized in that: In step 1 (1) and (5), the ruthenium salt is one or more of ruthenium chloride, nitric acid compound and acetylacetone compound.

3. The method for preparing a Ru-embedded TiO2 lattice-rich heterojunction interface hydrogen hydroxide evolution electrocatalyst according to claim 1, characterized in that: In step 1 (2) and (3), the ultrasonication time is 5 to 60 min.

4. A hydrogen hydroxide evolution electrocatalyst having Ru embedded in the TiO2 lattice and rich in heterojunction interface, prepared by any preparation method of claims 1 to 3.

5. The Ru-embedded TiO2 lattice-rich heterojunction interface hydrogen hydroxide evolution electrocatalyst of claim 4 is used in hydroxide exchange membrane fuel cells and water electrolysis devices.

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